FloridaBear has clearly made way too many assumptions to have any credibility...this is just more button pushing to try and curb the flood of new miners coming to the market.

Lets address the fallacy of his assumptions:

The assumption that Bitcoin will not go up is fundamentally and historically broken.  Infrastructure is getting better, the first convention/limited government is poised to add stability, and the its nowhere near public adoption yet, media coverage is expanding, and most importantly the capital expenditure in equipment and electricity supporting the network is growing exponentially.

He can't possibly be here trying to sell the idea that cryptos are going away, right?  Everything points to the opposite the same as Google, Facebook, apple, etc. etc.  So if Bitcoin is staying then we can easily (and more accurately) make the assumption the other way, that Bitcoin values will increase, and probably exponentially (as it catches on), and then linearly (linear growth will only be the norm when the global market is affected significantly by Bitcoin).   We can reliably look at the last 20 years of significant innovations growth models to arrive at this conclusion.

Granted you're analysis seems to have overlooked all of these core points.  Nonetheless, let me address a few of your other "assumptions".

"Altcoins are a fad" - certainly you'd have a case for unoriginal copies of Bitcoin being "doomed" in the long term

However, to ignore innovations like Litecoin, PPcoin, and other fundamentally different alt coins is ignoring the fundamental nature of new innovations (sometimes the first one to market doesn't always have the best product or the product that will dominate the marketplace).  It also ignores the fact that Google, Amazon, Microsoft, etc. etc...do not control 100% of their respective markets just because they were the first/biggest/etc.   Please at least demonstrate some basic market / economics knowledge before spreading the doom and gloom.  You're assumption's basis is purely opinion and lacks support.

"Altcoin profitability is a wash at best "-

 I think I read that you have a 7970 and if you do it suits you because its the one card that doesn't appreciably outperform its Bitcoin hash #'s when turned to scrypt mining.  However, even your 7970 does better (if we move the standard order of magnitude down mhash to khash) at mining scrypt than straight SHA 256.... GPU's are particularly good at scrypt in fact because of their high frequency memory and now increased mem capacities (thanks to graphics demands in larger screens/resolutions).   Most cards achieve up to 20% more khash on scrypt than on Bitcoin mining (Ex. a 7950 will usually do around 550-580 Mhash at stable temps and reasonable overclocking,  a properly setup 7950 on scrypt will be in the 670's on khash).  Given the conversion rate currently in place most educated scrypt miners are producing 15-30% more equivalent value on Litecoin today with the same hardware.

You've also failed to acknowledge that roughly 30THash worth of GPU's are or were running on the Bitcoin network and have been making their way over to Litecoin.   Guess what happens when all those resources and energy expenditures fortify Litecoin....the value goes up (Just like Bitcoin).

Every single one of your arguments really only holds water if:  All crypto currencies fail....and sorry to say but that's tin foil hat territory now.  Will there be economic shifts, government intervention, market crashes, etc?... Absolutely.   However, this genie isn't going back in the bottle and trying to scare off investments in mining serves zero purpose.  

Every mining rig in operation strengthens the integrity and the valuation of the cryptos.